Computers are ubiquitous in today's society. They come in all different varieties and can be found in places such as automobiles, laptops or home personal computers, banks, personal digital assistants, cell phones, as well as many businesses. In addition, as computers become more commonplace and software becomes more complex, there is a need for the computing devices to perform faster and more reliably in smaller and smaller packages.
As the design of computing systems continues to increase in complexity, certain tradeoffs are generally considered by a designer. For example, during design of an integrated circuit, such as a multi-core processor, analysis of the operation of the integrated circuit may be monitored and tested to improve the performance of the circuit. In particular, monitoring of a voltage in an integrated circuit allows for optimization of the power consumed by the circuit. Minimizing the voltage for a given operating frequency reduces the circuit operating power consumption. Lower power consumption for an integrated circuit design may be desirable over higher power consuming circuits. In addition, various levels of voltage noise may be present in an operating circuit or chip that can degrade the performance of the chip. Such so-called voltage droop may occur during heavy loading conditions. In this case, the amount of current demanded by the processor exceeds that which can be provided by the power supply and, as result, the power supply voltage at the transistor level droops. Thus, the ability to monitor and account for operational voltage noise, in addition to monitoring the power consumption of a design, aids in designing a better performing circuit.
Past circuit designs that allow for on-die voltage level measurement of the circuit typically employed one or more analog sensing pins that connect to a voltage meter. However, because these pins are typically located at the outer edge of the integrated circuit, the sensing pins do not accurately reflect the high frequency components of the circuit as the voltage signal is filtered before reaching the sensing pins. Thus, voltage measurement and performance analysis of an integrated circuit may become inaccurate at a high operating frequency. Further, as the operating frequency of integrated circuits increase, the performance monitoring of the circuits becomes less accurate. It is with these and other issues in mind that various aspects of the present disclosure were developed.